U.S. patent application number 13/989449 was filed with the patent office on 2013-09-12 for photosensitive negative resin composition.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. The applicant listed for this patent is Ken Ikegame, Masako Shimomura, Hyou Takahashi. Invention is credited to Ken Ikegame, Masako Shimomura, Hyou Takahashi.
Application Number | 20130235119 13/989449 |
Document ID | / |
Family ID | 46244611 |
Filed Date | 2013-09-12 |
United States Patent
Application |
20130235119 |
Kind Code |
A1 |
Takahashi; Hyou ; et
al. |
September 12, 2013 |
PHOTOSENSITIVE NEGATIVE RESIN COMPOSITION
Abstract
The invention provides a photosensitive negative resin
composition containing (a) an epoxy-group-containing compound, (b)
a first onium salt containing a cation portion structure
represented by (b1) and an anion portion structure represented by
(b2), and (c) a second onium salt containing a cation portion
structure represented by (c1) and an anion portion structure
represented by (c2). ##STR00001##
Inventors: |
Takahashi; Hyou;
(Kunitachi-shi, JP) ; Shimomura; Masako;
(Yokohama-shi, JP) ; Ikegame; Ken; (Ebina-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Takahashi; Hyou
Shimomura; Masako
Ikegame; Ken |
Kunitachi-shi
Yokohama-shi
Ebina-shi |
|
JP
JP
JP |
|
|
Assignee: |
CANON KABUSHIKI KAISHA
Tokyo
JP
|
Family ID: |
46244611 |
Appl. No.: |
13/989449 |
Filed: |
December 2, 2011 |
PCT Filed: |
December 2, 2011 |
PCT NO: |
PCT/JP2011/078501 |
371 Date: |
May 24, 2013 |
Current U.S.
Class: |
347/20 ;
430/280.1; 430/320 |
Current CPC
Class: |
G03F 7/004 20130101;
G03F 7/0046 20130101; B41J 2/1623 20130101; B41J 2/1628 20130101;
G03F 7/0045 20130101; G03F 7/038 20130101; B41J 2/1631
20130101 |
Class at
Publication: |
347/20 ;
430/280.1; 430/320 |
International
Class: |
G03F 7/004 20060101
G03F007/004 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2010 |
JP |
2010-280474 |
Claims
1. A photosensitive negative resin composition comprising (a) an
epoxy-group-containing compound, (b) a first onium salt containing
a cation portion structure represented by (b1) and an anion portion
structure represented by (b2), and (c) a second onium salt
containing a cation portion structure represented by (c1) and an
anion portion structure represented by (c2), ##STR00029## wherein
R.sub.1 to R.sub.3 are, independently of one another, an organic
group which may be substituted and has 1 to 30 carbon atoms, with
the proviso that at least two oxygen atoms are included in all the
constituent atoms of R.sub.1 to R.sub.3, X is selected from a
carbon atom, a nitrogen atom, a phosphorus atom, a boron atom and
an antimony atom, Y is selected from --S(.dbd.O).sub.2--, an
alkylene fluoride group, --OCF.sub.2--, --C(.dbd.O)--CF.sub.2--,
--O--C(.dbd.O)--CF.sub.2--, --C(.dbd.O)--O--CF.sub.2-- and a single
bond, R.sub.4 is a hydrocarbon group which may be substituted by a
fluorine atom and has 1 to 30 carbon atoms, and m and n are such
that m+n is 3 and n is an integer selected from 0, 1 and 2 when X
is the carbon atom, m+n is 2 and n is an integer selected from 0
and 1 when X is the nitrogen atom, m+n is 6 and n is an integer
selected from 0 to 6 when X is the phosphorus or antimony atom, or
m+n is 4 and n is an integer selected from 0 to 3 when X is the
boron atom, ##STR00030## wherein R.sub.5 to R.sub.7 are,
independently of one another, an organic group which may be
substituted and has 1 to 15 carbon atoms, with the proviso that at
most one oxygen atom is included in all the constituent atoms of
R.sub.5 to R.sub.7, Z is selected from a carbon atom and a sulfur
atom, k is 1 when Z is the carbon atom, k is 2 when Z is the sulfur
atom, and R.sub.8 is a hydrocarbon group which may contain a
heteroatom and has 1 to 20 carbon atoms.
2. The photosensitive negative resin composition according to claim
1, which satisfies the relationship, [The number of moles of the
first onium salt]>[The number of moles of the second onium
salt].
3. The photosensitive negative resin composition according to claim
1, wherein the component (b) has photosensitivity to at least the
i-line.
4. The photosensitive negative resin composition according to claim
1, wherein at least one of R.sub.1 to R.sub.3 contains a cyclic
carbonyl structure.
5. The photosensitive negative resin composition according to claim
1, wherein R.sub.8 contains an aromatic hydrocarbon or alicyclic
hydrocarbon.
6. The photosensitive negative resin composition according to claim
1, wherein Z is a sulfur atom.
7. The photosensitive negative resin composition according to claim
2, which satisfies the relationship, [The number of moles of the
first onium salt].times.0.7>The number of moles of the second
onium salt>[The number of moles of the first onium
salt].times.0.02.
8. The photosensitive negative resin composition according to claim
1, wherein X is a phosphorus atom.
9. A fine structure formed on a substrate, which is a cured product
of the photosensitive negative resin composition according to claim
1.
10. A liquid ejection head comprising a flow-path-forming layer
formed by the fine structure according to claim 9.
11. A process for forming a fine structure, comprising (1) a step
of arranging the photosensitive negative resin composition
according to claim 1 on a substrate, and (2) a step of subjecting
the photosensitive negative resin composition to a patterning
treatment by photolithography using the i-line.
Description
TECHNICAL FIELD
[0001] The present invention relates to a photosensitive negative
resin composition, and particularly to a photosensitive negative
resin composition suitable for forming a fine structure by a
photolithographic process.
BACKGROUND ART
[0002] As a microprocess technique, is known a photolithographic
technique in which a negative photosensitive resin is subjected to
exposure and development to form a pattern and a structure. This
technology is used in a wide variety of applications, for example,
production of semiconductor integrated circuits, production of
masks for semiconductor exposure and production of various MEMSs.
As an example of the application to the production of MEMSs, such
application is advanced in various small-scale sensors,
micro-probes, thin film magnetic heads, ink jet recording heads,
etc. A stepper using the i-line as a light source is widely used as
a device for conducting exposure. In the field of this technology,
it has been required in recent years to produce a structure having
a more complicated and minuter structure, and there has thus been a
demand for development of a negative photosensitive resin capable
of forming a fine structure exhibiting high accuracy to light from
a light source through a photomask.
[0003] PTL 1 discloses, as an example of the negative
photosensitive resin, a photosensitive resin composition containing
a polyfunctional epoxy resin and a cationic polymerization
initiator.
[0004] PTL 2 discloses, as an exemplary ink jet head in the
application to the production of MEMSs, a device containing nozzles
for ink jet head, said device ejecting an ink droplet by causing a
bubble formed by heating a heating resistor to communicate with the
air.
CITATION LIST
Patent Literature
[0005] PTL 1: Japanese Patent Application Laid-Open No. 2008-256980
[0006] PTL 2: Japanese Patent Application Laid-Open No.
H04-10940
SUMMARY OF INVENTION
Technical Problem
[0007] However, the above-described composition may have had
insufficient properties in the following point in some cases. As an
example, when a complicated form such as an ejection orifice having
a tapered form of a liquid ejection device is formed from the
negative photosensitive resin using the i-line as a light source,
the taper angle of the ejection orifice may vary in a chip or wafer
to fail to achieve desired reproducibility in some cases.
[0008] The present invention has been made in view of the above
problem and has as its object the provision of a photosensitive
negative resin composition which gives less dispersion and
excellent reproducibility of a three-dimensional form when a
photolithographic process is applied thereto.
Solution to Problem
[0009] In order to solve the above problem, the present invention
provides a photosensitive negative resin composition comprising
(a) an epoxy-group-containing compound, (b) a first onium salt
containing a cation portion structure represented by (b1) and an
anion portion structure represented by (b2), and (c) a second onium
salt containing a cation portion structure represented by (c1) and
an anion portion structure represented by (c2).
##STR00002##
wherein R.sub.1 to R.sub.3 are, independently of one another, an
organic group which may be substituted and has 1 to 30 carbon
atoms, with the proviso that at least two oxygen atoms are included
in all the constituent atoms of R.sub.1 to R.sub.3, X is selected
from a carbon atom, a nitrogen atom, a phosphorus atom, a boron
atom and an antimony atom, Y is selected from --S(.dbd.O).sub.2--,
an alkylene fluoride group, --OCF.sub.2--, --C(.dbd.O)--CF.sub.2--,
--O--C(.dbd.O)--CF.sub.2--, --C(.dbd.O)--O--CF.sub.2-- and a single
bond, R.sub.4 is a hydrocarbon group which may be substituted by a
fluorine atom and has 1 to 30 carbon atoms, and m and n are such
that m+n is 3 and n is an integer selected from 0, 1 and 2 when X
is the carbon atom, m+n is 2 and n is an integer selected from 0
and 1 when X is the nitrogen atom, m+n is 6 and n is an integer
selected from 0 to 6 when X is the phosphorus or antimony atom, or
m+n is 4 and n is an integer selected from 0 to 3 when X is the
boron atom.
##STR00003##
[wherein R.sub.5 to R.sub.7 are, independently of one another, an
organic group which may be substituted and has 1 to 15 carbon
atoms, with the proviso that at most one oxygen atom is included in
all the constituent atoms of R.sub.5 to R.sub.7, Z is selected from
a carbon atom and a sulfur atom, k is 1 when Z is the carbon atom,
or k is 2 when Z is the sulfur atom, and R.sub.8 is a hydrocarbon
group which may contain a heteroatom and has 1 to 20 carbon
atoms.]
Advantageous Effects of Invention
[0010] When the photosensitive negative resin composition according
to the present invention is used, a fine structure which gives less
dispersion and excellent reproducibility of a three-dimensional
form can be stably formed when a photolithographic process is
applied thereto. The photosensitive negative resin composition
according to the present invention is excellent in the
reproducibility when a photolithographic process using the i-line
is applied thereto in particular.
[0011] Further features of the present invention will become
apparent from the following description of exemplary embodiments
with reference to the attached drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a typical perspective view illustrating the
construction of an exemplary liquid ejection head.
[0013] FIG. 2 schematically illustrates a substrate having energy
generating elements.
[0014] FIGS. 3A, 3B, 3C, 3D, 3E and 3F are schematic process
drawings for illustrating an exemplary process for forming a fine
structure using a photosensitive negative resin composition
according to an embodiment.
[0015] FIGS. 4A, 4B, 4C, 4D, 4E and 4F are schematic process
drawings for illustrating another exemplary process for forming the
fine structure using the photosensitive negative resin composition
according to an embodiment.
[0016] FIG. 5 is a schematic sectional view of the liquid ejection
head illustrating a taper angle.
DESCRIPTION OF EMBODIMENTS
[0017] The photosensitive negative resin composition according to
the present invention will hereinafter be described in detail.
[0018] (a) Epoxy-Group-Containing Compound:
[0019] No particular limitation is imposed on the
epoxy-group-containing compound (hereinafter also abbreviated as
component (a)). However, the compound is favorably a polyfunctional
epoxy resin compound capable of conducting epoxy polymerization and
having a plurality of epoxy groups in its molecule. Examples of
such a polyfunctional epoxy resin include polyfunctional alicyclic
type epoxy resins, polyfunctional phenol/novolak type epoxy resins,
polyfunctional ortho-cresol novolak type epoxy resins,
polyfunctional triphenyl novolak type epoxy resins and
polyfunctional bisphenol A novolak type epoxy resins. Among these,
a polyfunctional bisphenol A novolak type epoxy resin,
polyfunctional alicyclic type epoxy resin or polyfunctional
phenol/novolak type epoxy resin is favorably used. The
functionality thereof is favorably penta- or higher functionality.
For example, "EPIKOTE 157S70" (product of Japan Epoxy Resin Co.,
Ltd.), "EPICLON N-865" (product of DIC Corporation) and "EHPE 3150"
(product of Daicel Corporation) are available as commercially
available products and more favorably used.
[0020] No particular limitation is imposed on the softening point
of the epoxy-group-containing compound. However, the softening
point is favorably 50.degree. C. or more, more favorably 60.degree.
C. or more. The softening point is favorably 180.degree. C. or
less, more favorably 160.degree. C. or less.
[0021] The content of the epoxy-group-containing compound in the
solid matter of photosensitive negative resin composition is
favorably 40% by mass or more, more favorably 60% by mass or more,
still more favorably 65% by mass or more. The content is favorably
99.9% by mass or less, more favorably 99.2% by mass or less. A
resist layer having high sensitivity and a proper hardness is
thereby obtained when such a composition is applied to a
substrate.
[0022] (b) First Onium Salt:
[0023] The first onium salt (hereinafter also abbreviated as
component (b)) is composed of a one-to-one combination of a cation
portion structure represented by (b1) and an anion portion
structure represented by (b2).
##STR00004##
[0024] In the cation portion structure represented by (b1), R.sub.1
to R.sub.3 are, independently of one another, an organic group
which may be substituted and has 1 to 30 carbon atoms, with the
proviso that at least two oxygen atoms are included in all the
constituent atoms of R.sub.1 to R.sub.3.
[0025] In the anion portion structure represented by (b2), X is
selected from a carbon atom, a nitrogen atom, a phosphorus atom, a
boron atom and an antimony atom, Y is selected from
--S(.dbd.O).sub.2--, an alkylene fluoride group, --OCF.sub.2--,
--C(.dbd.O)--CF.sub.2--, --O--C(.dbd.O)--CF.sub.2--,
--C(.dbd.O)--O--CF.sub.2-- and a single bond, R.sub.4 is a
hydrocarbon group which may be substituted by a fluorine atom and
has 1 to 30 carbon atoms, and m and n are such that m+n is 3 and n
is an integer selected from 0, 1 and 2 when X is the carbon atom,
m+n is 2 and n is an integer selected from 0 and 1 when X is the
nitrogen atom, m+n is 6 and n is an integer selected from 0 to 6
when X is the phosphorus or antimony atom, or m+n is 4 and n is an
integer selected from 0 to 3 when X is the boron atom.
[0026] Examples of (b1) and (b2) are mentioned. The feature of the
cation portion structure represented by (b1) resides in that the
photosensitivity to the i-line is high because the absorption
wavelength of the component (b) can be lengthened due to the
feature that at least two oxygen atoms are included. On the other
hand, the anion portion structure represented by (b2) is decomposed
with the component (b1) after exposure to generate an acid
originated from the structure of (b2). Thereafter, a cationic
polymerization reaction of the epoxy groups of the
epoxy-group-containing compound can be initiated and accelerated by
the action of the acid generated. The generated acid favorably has
such an acid strength that the epoxy-group-containing compound is
sufficiently cured. Such an acid strength that the
epoxy-group-containing compound is sufficiently cured means that
this acid is a strong acid not lower than hexafluoroantimonic acid
in terms of Lewis acid, i.e., that its Hammett acidity function
--HO is 18 or more. In terms of Br.phi.nsted acid, the acid
strength means that this acid is a strong acid not lower than
nanofluorobutane-sulfonic acid, i.e., that its PKa is -3.57 or
more.
##STR00005##
[0027] Favorable specific examples of the cation portion structure
represented by (b1) are mentioned below.
##STR00006## ##STR00007## ##STR00008## ##STR00009## ##STR00010##
##STR00011## ##STR00012## ##STR00013##
[0028] Among these, those containing a cyclic carbonyl structure
are favorable from the viewpoint that they have high
photosensitivity to the i-line, and examples of R.sub.1 to R.sub.3
containing the cyclic carbonyl structure include the
above-mentioned (b1-17) to (b1-30). R.sub.1 to R.sub.3 more
favorably contain a heterocyclic group containing a cyclic carbonyl
structure, and specific examples of R.sub.1 to R.sub.3 containing
the heterocyclic group containing the cyclic carbonyl structure
include the above-mentioned (b1-17) to (b1-24). At least one of
R.sub.1 to R.sub.3 favorably contains a cyclic carbonyl structure,
and more favorably two or more of R.sub.1 to R.sub.3 contain a
cyclic carbonyl structure. The carbonyl group is present in the
conjugated system, thereby greatly contributing to the lengthening
of the absorption wavelength of the first onium salt (b), and the
conjugated system contains the aromatic ring, thereby improving the
photosensitivity to the i-line in particular.
[0029] In the cation portion structure represented by (b1), it is
only necessary to include at least two oxygen atoms in all the
constituent atoms of R.sub.1 to R.sub.3 as described above, and one
or two of R.sub.1 to R.sub.3 may have a structure containing no
oxygen atom. Examples of structures that R.sub.1 to R.sub.3 may
take are described below. In the cation portion structure
represented by (b1), R.sub.1 to R.sub.3 are each, for example, an
aryl group having 6 to 30 carbon atoms in total, a heterocyclic
group having 4 to 30 carbon atoms in total, an alkyl group having 1
to 30 carbon atoms in total, an alkenyl group having 2 to 30 carbon
atoms in total or an alkynyl group having 2 to 30 carbon atoms in
total. These groups may be substituted by at least one selected
from the group consisting of, for example, respective groups of
alkyl groups, a hydroxyl group, cycloalkyl groups, alkenyl groups,
alkynyl groups, alkoxy groups, alkylcarbonyl groups, arylcarbonyl
groups, alkoxy-carbonyl groups, aryloxycarbonyl groups,
arylthio-carbonyl groups, acyloxy groups, arylthio groups,
alkylthio groups, aryl groups, heteroatom-containing aromatic ring
groups, aryloxy groups, alkylsulfinyl groups, arylsulfinyl groups,
alkylsulfonyl groups, arylsulfonyl groups, alkyleneoxy groups, an
amino group, a cyano group and a nitro group, and halogen atoms.
More specifically, examples of these substituents include
respective groups of alkyl groups (for example, methyl, ethyl,
propyl, isopropyl and butyl groups) having 1 to 6 carbon atoms, a
hydroxyl group, cycloalkyl groups (for example, cyclopropyl,
cyclobutyl, cyclopentyl and cyclohexyl groups) having 3 to 6 carbon
atoms, alkenyl groups (for example, vinyl, 1-propenyl, 2-propenyl
and 2-butenyl groups) having 2 to 6 carbon atoms, alkynyl groups
(for example, acetylenyl, 1-propinyl, 2-propinyl and 2-butynyl
groups) having 2 to 6 carbon atoms, alkoxy groups (for example,
methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy and tert-butoxy
groups) having 1 to 6 carbon atoms, alkylcarbonyl groups having 2
to 6 carbon atoms, arylcarbonyl groups having 7 to 11 carbon atoms,
alkoxycarbonyl groups (for example, methoxycarbonyl, ethoxycarbonyl
and tert-butoxycarbonyl groups) having 2 to 6 carbon atoms,
aryloxycarbonyl groups having 7 to 11 carbon atoms,
arylthiocarbonyl groups having 7 to 11 carbon atoms, acyloxy groups
having 2 to 6 carbon atoms, arylthio groups (for example,
phenylthio and naphthylthio groups) having 6 to 10 carbon atoms,
alkylthio groups (for example, methylthio, ethylthio, n-propylthio,
isopropylthio, n-butylthio and tert-butylthio groups) having 1 to 6
carbon atoms, aryl groups (for example, phenyl, naphthyl and
anthracenyl groups) having 6 to 14 carbon atoms,
heteroatom-containing aromatic ring groups (for example, furyl and
thienyl groups) having 4 to 8 carbon atoms, aryloxy groups (for
example, phenoxy and naphthoxy groups) having 6 to 10 carbon atoms,
alkylsulfinyl groups having 1 to 6 carbon atoms, arylsulfinyl
groups having 6 to 10 carbon atoms, alkylsulfonyl groups having 1
to 6 carbon atoms, arylsulfonyl groups having 6 to 10 carbon atoms,
alkyleneoxy groups having 1 to 6 carbon atoms, an amino group, a
cyano group and a nitro group, and halogen atoms (for example,
chlorine, bromine and fluorine atoms). R.sub.1 to R.sub.3 may be
the same or different from one another. Two or more R groups of
R.sub.1 to R.sub.3 may also be bonded directly or through --O--,
--S--, --SO--, --SO.sub.2--, --NH--, --NR.sub.a--, --CO--,
--C(.dbd.O)O--, --C(.dbd.O)NH--, an alkylene group having 1 to 3
carbon atoms or a phenylene group to each other to form a ring
structure. Here, R.sub.a is an alkyl group having 1 to 5 carbon
atoms or an aryl group having 6 to 10 carbon atoms. Incidentally,
the alkyl group in the present specification includes a linear
chain, branched chain or cyclic chain.
[0030] Favorable specific examples of the anion portion structure
represented by (b2) are mentioned below.
##STR00014## ##STR00015## ##STR00016##
[0031] In the anion portion structure represented by (b2), R.sub.4
is favorably a hydrocarbon group having at least one fluorine atom
when n is 0 and Y is --S(.dbd.O).sub.2-- or a single bond. When m
is 2 or more, any carbon atom of one R.sub.4 and any carbon atom of
another R.sub.4 may also be bonded through a single bond to each
other to form a ring structure. R.sub.4 is, for example, an alkyl
or aryl group which may be substituted by a fluorine atom.
[0032] In the anion portion structure represented by (b2), X is
favorably a phosphorus atom, and specific examples of such a
structure include the above-mentioned (b2-11) to (b2-18). In the
case of the Lewis acid system, i.e., case where X is an antimony or
phosphorus atom, a cured film formed tends to have excellent heat
resistance. In the case where X is a phosphorus atom, a
metal-corroding tendency is less than the case where X is antimony
atom.
[0033] The component (b) may be used singly or in a combination of
2 or more thereof.
[0034] The content of the component (b) is favorably 0.01 parts by
mass or more, more favorably 0.1 parts by mass or more per 100
parts by mass of the photosensitive negative resin composition. The
content is favorably 20 parts by mass or less, more favorably 10
parts by mass or less.
[0035] (C) Second Onium Salt:
[0036] The second onium salt (hereinafter also abbreviated as
component (c)) is composed of a one-to-one combination of a cation
portion structure represented by (c1) and an anion portion
structure represented by (c2) that are respectively specific
structures.
##STR00017##
[0037] In the cation portion structure represented by (c1), R.sub.5
to R.sub.7 are, independently of one another, an organic group
which may be substituted and has 1 to 15 carbon atoms, with the
proviso that at most one oxygen atom is included in all the
constituent atoms of R.sub.5 to R.sub.7.
[0038] In the anion portion structure represented by (c2), Z is
selected from a carbon atom and a sulfur atom. k is 1 when Z is the
carbon atom, or k is 2 when Z is the sulfur atom. R.sub.8 is a
hydrocarbon group which may contain a heteroatom and has 1 to 20
carbon atoms.
[0039] In the present invention, it is important that the second
onium salt (c) is contained in addition to the first onium salt
(b). The reason for this is as follows. As described above, the
acid (b2) generated from the first onium salt (b) after exposure to
the i-line is a strong acid and initiates and accelerates the
cationic polymerization reaction of the epoxy groups, and so the
component (b) is suitable for photosensitization in this point. On
the other hand, when the acid (b2) diffuses into the photosensitive
negative resin composition, an unexposed portion which will becomes
an ejection orifice is cured, and it may thus be difficult in some
cases to stably form an ejection orifice form. Thus, the second
onium salt (c) composed of the cation portion structure represented
by (c1) and the anion portion structure represented by (c2) is used
in the present invention. In particular, supposing an acid with a
proton imparted to the anion portion structure represented by (c2),
the anion portion structure represented by (c2) has a structure of
a weak acid that cannot cause epoxy polymerization or is very low
in acidity to cause the polymerization. Accordingly, when the acid
(b2) generated from the first onium salt (b) meets the second onium
salt (c), salt exchange occurs, and the acid is converted to a weak
acid that cannot cause epoxy polymerization or is hard to cause the
polymerization. In short, the second onium salt (c) can function as
a good quencher for the acid accelerating the epoxy polymerization
in the epoxy polymerization. The feature of the cation portion
structure represented by (c1) resides in that the photosensitivity
to the i-line is low due to the structure that at most one oxygen
atom is included in all the constituent atoms of R.sub.5 to
R.sub.7. It can thereby be inhibited that the second onium salt (c)
is sensitized to light upon exposure. As described above, the first
onium salt and the second onium salt synergistically act in the
present invention, whereby a fine structure which gives less
dispersion and excellent reproducibility of a three-dimensional
form can be stably formed.
[0040] Examples of (c1) and (c2) are mentioned below.
##STR00018##
[0041] In the cation portion structure represented by (c1), R.sub.5
to R.sub.7 are each, for example, an aryl group having 6 to 15
carbon atoms in total or an alkyl group having 1 to 15 carbon atoms
in total. These groups may be substituted by at least one selected
from the group consisting of, for example, respective groups of
alkyl groups, fluoroalkyl groups, a hydroxyl group, cycloalkyl
groups, alkoxy groups, alkylcarbonyl groups, arylcarbonyl groups,
arylthio groups, alkylthio groups, aryl groups and aryloxy groups,
and halogen atoms. More specifically, examples of these
substituents include respective groups of alkyl groups (for
example, methyl, ethyl, propyl, isopropyl and butyl groups) having
1 to 6 carbon atoms, fluoroalkyl groups (for example,
trifluoromethyl and pentafluoroethyl groups) having 1 to 6 carbon
atoms, a hydroxyl group, cycloalkyl groups (for example,
cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups) having
3 to 6 carbon atoms, alkoxy groups (for example, methoxy, ethoxy,
n-propoxy, isopropoxy, n-butoxy and tert-butoxy groups) having 1 to
6 carbon atoms, alkylcarbonyl groups having 2 to 6 carbon atoms,
arylcarbonyl groups having 7 to 11 carbon atoms, arylthio groups
(for example, phenylthio and naphthylthio groups) having 6 to 10
carbon atoms, alkylthio groups (for example, methylthio, ethylthio,
n-propylthio, isopropylthio, n-butylthio and tert-butylthio groups)
having 1 to 6 carbon atoms, aryl groups (for example, phenyl and
naphthyl groups) having 6 to 10 carbon atoms and aryloxy groups
(for example, phenoxy and naphthoxy groups) having 6 to 10 carbon
atoms, and halogen atoms (for example, chlorine, bromine and
fluorine atoms). R.sub.5 to R.sub.7 may be the same or different
from one another. Two or more R groups of R.sub.5 to R.sub.7 may
also be bonded directly or through an alkylene group having 1 to 3
carbon atoms or a phenylene group to each other to form a ring
structure.
[0042] Favorable specific examples of the cation portion structure
represented by (c1) are mentioned below.
##STR00019## ##STR00020## ##STR00021##
[0043] In the anion portion structure represented by (c2), R.sub.8
is, for example, an alkyl group having 1 to 20 carbon atoms in
total or an aryl group having 6 to 20 carbon atoms in total. These
groups may be substituted by at least one selected from the group
consisting of, for example, alkyl groups, an oxo group, cycloalkyl
groups, alkoxy groups and alkylcarbonyl groups. More specifically,
examples of these substituents include alkyl groups (for example,
methyl, ethyl, propyl, isopropyl and butyl groups) having 1 to 10
carbon atoms, cycloalkyl groups (for example, cyclopropyl,
cyclobutyl, cyclopentyl and cyclohexyl groups) having 3 to 6 carbon
atoms, alkoxy groups (for example, methoxy, ethoxy, n-propoxy,
isopropoxy, n-butoxy and tert-butoxy groups) having 1 to 6 carbon
atoms, alkylcarbonyl groups having 2 to 6 carbon atoms. Two or more
carbon atoms of R.sub.8 may also be bonded directly or through an
alkylene group having 1 to 3 carbon atoms to each other to form a
ring structure. The ring structure may be monocyclic or
polycyclic.
[0044] Favorable specific examples of the anion portion structure
represented by (c2) are mentioned below.
##STR00022## ##STR00023## ##STR00024## ##STR00025## ##STR00026##
##STR00027##
[0045] In the anion portion structure represented by (c2), R.sub.8
is favorably an aromatic hydrocarbon- or alicyclic
hydrocarbon-containing structure. When R.sub.8 is the aromatic
hydrocarbon- or alicyclic hydrocarbon-containing structure, it is
inhibited due to its bulkiness and carbon density that an acid
generated from the anion represented by (c2) is volatilized during
a heating process and vaporized off in an atmospheric environment.
Specific examples of the anion portion structure having R.sub.8
containing the aromatic hydrocarbon or alicyclic hydrocarbon
include the above-mentioned (c2-1) to (c2-11), (c2-17) to (c2-25),
(c2-28) to (c2-40), and (c2-48) to (c2-56).
[0046] In the anion portion structure represented by (c2), Z is
favorably a sulfur atom. When Z is the sulfur atom, the anion can
be more stabilized compared with the case where Z is the carbon
atom. Therefore, the nucleophilicity of the anion portion can be
inhibited to inhibit the decomposition of the second onium salt
caused by the anion portion nucleophilically attacking the cation
portion of (c1).
[0047] The component (c) may be used singly or in a combination of
2 or more thereof.
[0048] The content of the component (c) is favorably 0.001 parts by
mass or more per 100 parts by mass of the photosensitive negative
resin composition. The content is favorably 5 parts by mass or
less, more favorably 4 parts by mass or less.
[0049] The amounts of the component (b) and the component (c)
incorporated into the photosensitive negative resin composition
favorably satisfy the following relationship.
[0050] The number of moles of the first onium salt (b)>The
number of moles of the second onium salt (c)
[0051] When this relationship is satisfied, a state where the
amount of the component (b) generating the acid effective for the
epoxy polymerization is more than the amount of the component (c)
functioning as a quencher is created, whereby high
photosensitization can be achieved.
[0052] The both components also favorably satisfy the following
relationship.
[The number of moles of the first onium salt (b)].times.0.7>The
number of moles of the second onium salt (c)>[The number of
moles of the first onium salt (b)].times.0.02
[0053] The amount of the second onium salt (c) added is increased
to make the number of moles of the second onium salt (c) greater
than [The number of moles of the first onium salt (b)].times.0.02,
whereby the effect of the second onium salt as the quencher can be
sufficiently achieved.
[0054] The photosensitive negative resin composition according to
the present invention may also contain a third onium salt in
addition to the first onium salt (b) and the second onium salt (c).
Examples of the third onium salt include those containing the
cation portion structure represented by (c1) and the anion portion
structure represented by (b2). In this case, the content of the
third onium salt is favorably, for example, 0.001 parts by mass or
more, more favorably 0.005 parts by mass or more per 100 parts by
mass of the photosensitive negative resin composition. The content
is favorably 25 parts by mass or less, more favorably 15 parts by
mass or less.
[0055] As described above, the photosensitive negative resin
composition according to the present invention is used, whereby a
fine structure which gives less dispersion and excellent
reproducibility of a three-dimensional form can be stably formed.
The photosensitive negative resin composition according to the
present invention is excellent in the reproducibility when a
photolithographic process using the i-line is applied thereto in
particular.
[0056] A nitrogen-atom-containing organic compound, particularly,
an amine compound may be used in some cases as a quencher for acid.
However, when such an epoxy-group-containing compound as used in
the present invention is mixed with the amine compound, the amine
compound functions as a curing agent, and curing may proceed in
some cases in a dark reaction. Therefore, it is difficult to store
the amine compound in a state of being mixed with such an
epoxy-group-containing compound as used in the present invention
for a long period of time. On the other hand, the component (c) of
the present invention generates extremely small dark reactions even
when mixed with the epoxy-group-containing compound, so that it is
possible to store the component (c) in a state of being mixed with
the epoxy-group-containing compound for a long period of time.
[0057] Production Method:
[0058] For example, a liquid ejection head can be formed by using
the photosensitive negative resin composition according to the
present invention. No particular limitation is imposed on the
liquid ejection head. However, an ink jet recording head is
mentioned as an example thereof.
[0059] FIG. 1 is a typical perspective view illustrating the
construction of an exemplary ink jet recording head. The ink jet
recording head illustrated in FIG. 1 has a flow-path-forming layer
4 forming ink ejection orifices (ejection orifices) 5 and an ink
flow path (liquid flow path) 3c communicating with the ink ejection
orifices 5 on a substrate having a plurality of energy-generating
elements 2. An ink supply port (liquid supply port) 6 for supplying
an ink (liquid) to the ink flow path 3c is provided in the
substrate 1. As illustrated in FIG. 2, a plurality of the
energy-generating elements 2 are arranged at a predetermined pitch
on the substrate 1.
[0060] A production method of the ink jet recording head will
hereinafter be described with reference to FIGS. 3A to 3F and FIGS.
4A to 4F. FIGS. 3A to 3F and FIGS. 4A to 4F correspond to sectional
views taken along line 3-3 in FIGS. 1 and 2. Incidentally, the
production methods illustrated in FIGS. 3A to 3F and FIGS. 4A to 4F
are referred to as Production Method 1 and Production Method 2,
respectively.
[0061] Incidentally, a control signal input electrode (not
illustrated) for operating the element is connected to each
energy-generating element 2.
Production Method 1:
[0062] A substrate 1 having energy-generating elements 2 is first
provided as illustrated in FIG. 3A.
[0063] The substrate 1 is favorably an Si substrate, particularly
favorably a silicon single crystal. When a through-hole is provided
in the substrate 1 by anisotropic etching, the substrate is
favorably a silicon single crystal having the crystal orientation
<100>. When a through-hole is provided in the substrate 1 by
dry etching, sand blasting or laser machining, the substrate may be
a silicon single crystal having the crystal orientation
<110>.
[0064] No particular limitation is imposed on the energy-generating
elements 2 so far as election energy for ejecting an ink droplet
can be given to the ink to eject the ink droplet from the ejection
orifice. For example, when heating resistor elements are used as
the energy-generating elements, the heating resistor element heats
an ink present in the vicinity thereof, thereby causing the ink to
bring about a change of state to generate ejection energy.
[0065] A soluble resin composition is then applied on to the
substrate 1 to form a soluble resin layer 3a for ink flow path
pattern as illustrated in FIG. 3B.
[0066] As a method for forming the soluble resin layer 3a, for
example, a positive photosensitive resin is suitably dissolved in a
solvent, and the solution is applied on to the substrate 1 by a
spin coating method. Thereafter, the solution applied is heated,
whereby the soluble resin layer 3a can be formed. No particular
limitation is imposed on the thickness of the soluble resin layer
3a so far as it corresponds to a desired height of the ink flow
path. However, the thickness is favorably, for example, 2 to 50
.mu.m.
[0067] The soluble resin layer 3a is then irradiated with radiation
and developed, thereby forming an ink flow path pattern 3b as
illustrated in FIG. 3C.
[0068] The photosensitive negative resin composition according to
the present invention is then arranged on the ink flow path pattern
3b and the substrate 1 to form a flow-path-forming layer 4.
[0069] The thickness of the flow-path-forming layer 4 is favorably
2 .mu.m or more in terms of the thickness on the ink flow path
pattern 3b. No particular limitation is imposed on the upper limit
of this thickness. However, the upper limit is, for example, 100
.mu.m or less in terms of the thickness on the ink flow path
pattern 3b in view of the developability of ink ejection orifice
portions.
[0070] The flow-path-forming layer 4 is then irradiated with the
i-line and developed with MIBK (methyl isobutyl ketone) to conduct
a patterning treatment. A rinsing treatment with IPA is then
conducted, thereby forming ink ejection orifices 5 (FIG. 3D).
[0071] The center wavelength of the i-line is 365 nm.
[0072] An ink supply port 6 is then formed by means of a proper
method such as an etching treatment as illustrated in FIG. 3E.
[0073] The ink flow path pattern 3b is then dissolved out with a
proper solvent as illustrated in FIG. 3F.
[0074] As the solvent, may be used, for example, an aqueous alkali
solution or an organic solvent.
[0075] Thereafter, the substrate 1 is cut and separated into chips
by a dicing saw, and electrical junction for driving the
energy-generating elements 2 is formed. In addition, a chip tank
member for supplying an ink is connected to complete an ink jet
recording head.
[0076] Incidentally, the above-described method is also useful as a
pattern-forming method for forming a hollow pattern without being
limited to the production method of the ink jet recording head.
[0077] Production Method 2:
[0078] A soluble resin composition is first applied on to a
substrate 1 to form an ink flow path pattern 3b as illustrated in
FIG. 4A.
[0079] A flow-path-forming layer 4 formed of the photosensitive
negative resin composition according to the present invention is
then formed on the ink flow path pattern 3b and the substrate 1 as
illustrated in FIG. 4B.
[0080] The flow-path-forming layer 4 is then irradiated with the
i-line through a first photomask 10 as illustrated in FIG. 4C. When
post first exposure baking is conducted for this flow-path-forming
layer, surface recesses 7 and first ejection orifice patterns 8a
that are latent images of ejection orifices are formed. No
particular limitation is imposed on the conditions for the post
first exposure baking. However, this baking is, for example, a heat
treatment for 4 minutes at 100.degree. C.
[0081] The flow-path-forming layer 4 is then irradiated again with
the i-line through a second photomask 11 as illustrated in FIG. 4D.
The second photomask 11 has opening portions different from the
first photomask 10. At this time, at least part of unexposed
portions after the first exposure are subjected to second exposure.
When post second exposure baking is conducted for this
flow-path-forming layer, second ejection orifice patterns 8b that
are latent images of ejection orifices are newly formed. No
particular limitation is imposed on the conditions for the post
second exposure baking. However, this baking is, for example, a
heat treatment for 4 minutes at 90.degree. C.
[0082] The second photomask 11 includes circular or oval
light-screening portions corresponding to an ejection orifice for
forming ejection orifices. The first photomask 10, on the other
hand, includes light-screening portions at the same positions as
the light-screening portions for ejection orifices of the second
photomask 11, and these light-screening portions each have an area
larger than that of the second photomask 11 to cover the
light-screening portion of the second photomask 11.
[0083] The flow-path-forming layer 4 is then developed with MIBK
(methyl isobutyl ketone). In addition, a rinsing treatment is
conducted with IPA, thereby forming ejection orifices 5 as
illustrated in FIG. 4E.
[0084] An ink supply port 6 is then formed by means of a proper
method such as an etching treatment as illustrated in FIG. 4F. The
ink flow path pattern 3b is then dissolved out with a proper
solvent to form an ink flow path 3c.
[0085] Thereafter, the substrate 1 is cut and separated into chips
by a dicing saw, and electrical junction for driving the
energy-generating elements 2 is formed. In addition, a chip tank
member for supplying an ink is connected to complete an ink jet
recording head.
[0086] Incidentally, the above-described method is also useful as a
pattern-forming method for forming a hollow pattern without being
limited to the production method of the ink jet recording head.
EXAMPLES
[0087] The present invention will hereinafter be described by
[0088] Examples. However, the present invention is not limited to
these Examples.
Example 1
[0089] Components (a), (b) and (c) were mixed according to the
formulation shown in Table 1, and propylene glycol monomethyl ether
as a solvent was additionally mixed in an amount of 80 parts by
mass per 100 parts by mass of the component (a) to obtain a
photosensitive negative resin composition. In Table 1, the unit is
part(s) by mass.
[0090] After this photosensitive negative resin composition was
applied on to a substrate composed of a silicon wafer by a spin
coater, prebaking and drying were conducted for 5 minutes at
90.degree. C. to obtain a photosensitive resin composition layer
having a thickness of 40 .mu.m. After the prebaking, patterning
exposure was conducted through a mask, in which a desired pattern
had been formed, by means of FPA-3000 i5+ (i-line stepper;
manufactured by Canon Inc.) according to the above-described
Production Method 1 and Production Method 2, and a post exposure
baking treatment was conducted for 4 minutes at 90.degree. C. on a
hot plate.
[0091] Incidentally, in Production Method 1, the thickness of the
flow-path-forming layer 4 formed of the photosensitive negative
resin composition was controlled to 20 .mu.m in terms of the
thickness on the ink flow path pattern 3b. In Production Method 2,
the thickness of the flow-path-forming layer 4 formed of the
photosensitive negative resin composition was controlled to 25
.mu.m in terms of the thickness on the ink flow path pattern
3b.
[0092] In Production Method 1, the defocus setting of the i-line
stepper was suitably changed, whereby a taper angle of, for
example, about 0.1 to 10.degree. can be achieved. This example was
performed in such a manner that the taper angle was 5.degree. in
Production Method 1 and 10.degree. in Production Method 2.
Thereafter, CDS-860R+(manufactured by Canon Inc.) was used to
conduct a development treatment. The resin pattern after the
development was post-baked together with the substrate for 1 hour
at 140.degree. C. by means of an oven to obtain a cured resist
pattern on the substrate.
[0093] Evaluation:
[0094] A taper angle that 90 degrees--9 illustrated in FIG. 5 was
calculated from a section photograph obtained by observing through
SEM in a direction of the sectional view taken along line 3-3 in
FIG. 1 or 2. The measurement was conducted on each of five ejection
orifices in the same pattern. The value (%) obtained by calculating
a difference between the average value of the five taper angles
thus obtained and the value most different from the average value,
dividing the difference calculated by the average value and
multiplying this value by 100 was defined as the taper angle
dispersion.
Examples 2 to 6, and 8
[0095] Photosensitive negative resin compositions were prepared in
the same manner as in Example 1 except that components (a), (b) and
(c) were used according to their corresponding formulations shown
in Table 1, and the evaluation was made.
Exmple 7
[0096] A photosensitive negative resin composition was prepared in
the same manner as in Example 1 except that components (a), (b),
(c) and (d) were used according to the formulation shown in Table
1, and the evaluation was made. The component (d) is such that the
cation portion structure is the following compound represented by
c1-21, and the anion portion structure is b2-23.
[0097] (c1-21)
##STR00028##
Example 9
[0098] A photosensitive negative resin composition was prepared in
the same manner as in Example 1 except that components (a), (b) and
(c) and a sensitizer were used according to the formulation shown
in Table 1, and the evaluation was made. As the sensitizer e-1, was
used 1-naphthol.
Comparative Examples 1 and 2
[0099] Photosensitive negative resin compositions were prepared in
the same manner as in Example 1 except that components (a) and (d)
were used according to their corresponding formulations shown in
Table 1, and the evaluation was made.
Comparative Example 3
[0100] A photosensitive negative resin composition was prepared in
the same manner as in Example 1 except that components (a) and (b)
were used according to the formulation shown in Table 1, and the
evaluation was made.
[0101] Incidentally, Examples 1 to 9 and Comparative Example 3 all
satisfy the relationship of "The number of moles of the first onium
salt>The number of moles of the second onium salt".
TABLE-US-00001 TABLE 1 Example Comparative Example Mixed components
1 2 3 4 5 6 7 8 9 1 2 3 Component a-1 100 -- -- 100 100 -- -- -- --
100 100 100 (a) a-2 -- 100 100 -- -- 100 -- -- -- -- -- -- a-3 --
-- -- -- -- -- 100 100 100 -- -- -- Component b1-17/b2-11 2 2 -- --
-- -- 1 2 1 -- -- 2 (b) b1-18/b2-12 -- -- 2 -- -- -- -- -- -- -- --
-- b1-25/b2-11 -- -- -- 2 -- -- -- -- -- -- -- -- b1-1/b2-1 -- --
-- -- 5 -- -- -- -- -- -- -- b1-17/b2-23 -- -- -- -- -- 3 -- -- --
-- -- -- Component c1-1/c2-1 .sup. 0.5 -- -- -- -- -- .sup. 0.5 --
-- -- -- -- (c) c1-2/c2-2 -- .sup. 0.5 -- -- -- -- -- .sup. 0.5 --
-- -- -- c1-5/c2-7 -- -- .sup. 0.5 -- -- -- -- -- -- -- -- --
c1-13/c2-8 -- -- -- .sup. 0.5 -- -- -- -- -- -- -- -- c1-2/c2-6 --
-- -- -- .sup. 0.5 -- -- -- -- -- -- -- c1-1/c2-26 -- -- -- -- --
.sup. 0.5 -- -- -- -- -- -- c1-19/c2-14 -- -- -- -- -- -- -- --
0.25 Component c1-21/b2-23 -- -- -- -- -- -- 4 -- -- 3 3 -- (d)
Sensitizer e-1 -- -- -- -- -- -- -- -- 0.10 -- -- -- Taper angle
Production Method 1 3% -- 4% 3% 5% -- -- 4% 6% 12% -- 15%
dispersion Production Method 2 -- 2% -- -- -- 4% 2% -- 5% -- 10% --
(a-1): EPICLON N-865 (trade name, product of DIC Corporation)
(a-2): JER157S70 (trade name, product of Japan Epoxy Resin Co.,
Ltd.) (a-3): EHPE 3150 (trade name, product of Daicel
Corporation).
[0102] In Examples 1 to 9, the respective photosensitive negative
resin compositions containing the components (b) and (c) were used
to determine the taper angle dispersion of the ejection orifices.
As a result, the dispersion was 5% or less, and so high
reproducibility was achieved.
[0103] On the other hand, in the photosensitive negative resin
compositions of Comparative Examples 1 to 3, the taper angle
dispersion was 10% to 15%, and so the reproducibility of the taper
angle was insufficient.
INDUSTRIAL APPLICABILITY
[0104] From the above, the photosensitive negative resin
compositions according to the present invention can reproduce the
taper angle with good results and can stably form a fine structure
which gives less dispersion and excellent reproducibility of a
three-dimensional form. Accordingly, the photosensitive negative
resin compositions according to the present invention can be
suitably used in various devices subjected to microprocessing for
MEMS.
[0105] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0106] This application claims the benefit of Japanese Patent
Application No. 2010-280474, filed Dec. 16, 2010, which is hereby
incorporated by reference herein in its entirety.
REFERENCE SIGNS LIST
[0107] 1 Substrate [0108] 2 Energy-generating elements [0109] 3a
Soluble resin layer [0110] 3b Ink flow path pattern [0111] 3c Ink
flow path [0112] 4 Flow-path-forming layer [0113] 5 Ejection
orifices [0114] 6 Ink supply port [0115] 7 Surface recesses [0116]
8a First ejection orifice patterns [0117] 8b Second ejection
orifice patterns [0118] 9 90 Degrees--taper angle [0119] 10 First
photomask [0120] 11 Second photomask
* * * * *